Stabilization of fatty materials



Patented Sept. 5, 1944 UNITED STATES PATENT oFFicE STABILIZATION .OF FATTY Guy W. Phelps and Howard 0. Black, Chicago,

111., assignors to Industrial Patents Corporation, Chicago, 111., a corporation of Delaware No Drawing. Application November 10, 1941,

' Serial No. 418,553

9 Claims. This invention relates to the stabilization of fatty materials and more particularly it is dito revert occurs in three distinctphases which are generally found to be dueto the action of light, air, and heat. The first step is a definite change from a bland, odorless, and tasteless oil to one of metallic, pungent, oraged flavor typical for each reverting oil. This flavor is very distinct from that characteristic of rancidity. The second step is one where the characteristic flavor of rancidity develops to a point of blending with or even partially masking the reverted odor and flavor. The third or final step is approached rapidly from the second step, and is due to a .rather vigorous breakdown of products formed during the first two stages. The net result is the formation of volatile decomposition products yvhich'are responsible for the strong, acrid, and biting flavor and odor of very rancid fatty materials. Although many stabilizers have been described as inhibitors for rancidity, until now there has not been a onvenient and satisfactory method for preve ting reversion of fatty materials. 1 v I The prevention of reversion of fatty materials is now possible by a simple and economical procedure involving the use of'a particular type agent modified to a definite degree and employed in a specific manner. This result is unpredictable and startling since the same material not modified in the same manner or employed at a diflerent point in the processing of fatty oils will not effect the reversion resistance obtained with the present invention.

It has been discovered that the steam deodorization of fatty materials in the presence of asame agents either non-hydrogenated or hydrogenated, refined or crude, in the fatty material subsequent to the deodorization step. Furthermore, if the agent is not hydrogenated to a. melting point of at least 100 F., then the effectiveness, of the agent during deodorization to increase the reversion resistance. of the fatty material under treatment does not exist substantial degree.

It has also been discovered that during the deodorization of the fatty material in the presence ofone or more of these agents the step of to any heating the steam vapors leaving the body of fatty material so that there is no tendency to reflux, not only substantially shortens the period of treatment and permits lower liquid temperatures with consequent minimization of hydrolysis, but also brings about the removal of many impurities not previously separated and causes less breakdown of the product under treatment. The products are of even better color, odor, taste, and have greater resistance to reverting and degrading, i

In general the treatment of the fatty material in the preparation of edible product s involves the following steps: Refining by treatment with alkali followed by centrifugation, or by solvent extraction in order to remove fatty acids, gums, and re.

defined soy bean oil or sesame oil, which has been hydrogenated until the melting point is at least 100 R, will produce a product having exceptional reversion resistance and outstanding stability. Surprisingly enough the material need the high melting point of this product it can be used as a bodyingor hardening agent for softer,

i'atty preparations, e. g. in the preparation of compound shortenings. Small quantities can be used without altering the physical properties of the fatty material, but large proportions will as ,sist in raising the melting p int and increasing the hardness'of more liquid fatty materials. The mechanism' 'of this reversion resistance is not completely understood, but it appears to be engtirely difl'erentfrom the incorporation of the lated materials; bleaching and filtering with fullers earth: hydrogenatin the fatty material, if necessary, in the presence of a nickel catalyst: filtering with or without filter aids, such as kiesel- 'guhr, fullers earth or filtercel; and'then deodorizetion in the following manner. a

The deodorizing treatment of the fatty material is generally carried out according to the invention by placing liquid or liquified crude and/or refined fatty material along with about 0.5% to 5% of the strongly hydrogenated refined soy bean or sesame oil, or mixtures thereof, into a heated, closed vessel having open steam ports in the bottom thereof. The material, at a tem- I perature of about 200 to 450 F., depending on the nature of the composition under treatment, is usually subjected to a vacuum, generally about twenty to thirty inches of'mercury, e. g. twentynine inches, while passing steam therethrough at a temperature slightly above that of the material under treatment.

Heat is preferably applied in the upper part of the vessel either directly by steam or preferably by indirect means so that the vapors which are withdrawn near the top are prevented from cooling materially and are preferably raised in temperature thereby preventing substantial condensation' and reflux of vaporized impurities. The temperature in the upper part of the vessel is advantageously maintained at the temperature of or near the temperature of the liquid, preferably at a temperature of at least about 250 F.

This may be obtained by passing steam, mineral oilvaporiidiphenyl vapor, diphenyl ether vapor, or otlier suitable vapors or mixed vapors, heat exchange liquids including molten salts or {the like, through passages, pipes, tubes, zones or other indirect heating means in the vapor path, in the walls and/or the outside of the deodorizing vessel.

The-vapors are withdrawn near the top of the vessel and passed through a condenser to recover high boiling organic materials, then to a steameiector and finally a barometric condenser wherein the steam is condensed.

The reversion resistance and stability of the deodorized product is surprisingly increased. Furthermore, the products obtained from this procedure have a substantially lower impurity content, particularly of a fatty acid nature, and the smoke point thereof is raised considerably. These improved results are obtained with treating for only a fraction of the time normally employed.

Absolute values cannot be fixed for the deodorization treatment of all fatty materials because of the variable nature of the valuable constituents thereof as well as the impurities therein. For example, it has been found that for operation in the deodorization of vegetable oils of various types, it is desirable to employ oil temperatures of the order of 350 to 450 F. Steam is usually introduced in ,such a heated mixture at a pressure of about 50 to 150 pounds per square inch and a temperature of about 300 to 400 F.

' In such operation the temperature of the vapors is preferably kept at a value of 250 to 350 F. or

higher in order to avoid condensation, whereas in prior practice, temperatures below 200 F. to 250 F. were normally existent.

n the other hand, with animal fats it has now been found that although the above operating temperatures are effective, even more desirable results are obtained by employing oil temperature of 200 to 300 1'2, preferably at least 250 F., with slightly lower vapor and steam temperatures than those employed in the vegetable oiltreatment.

The following examples are given for the purpose of illustrating the present invention but are not intended to be limiting on the scope thereof.

A series of animal fats, namely, oleo oil, lard and edible tallow, obtained by rendering were alkali refined, filtered and then deadorlzed with steam at a temperature between 350 and 450 F.

the addition of the antioxidant inhibitor to the fat prior to deodorization greatly inhibits reversion. Such results could not be termed predictable in view of the present state of the art.

Although the .above examples are directed to the treatment of animal fats, similar results are obtained with vegetable oils and fats by the incorporation of one of the two type antioxidants prior to the deodorization treatment. Among the materials whichmay be improved by the present means are olive oil, butter, lard, cottonseed oil, soy beon oil, peanut oil, tallow, sesame oil, coconut oil, palm oil, palm kernel oil, safllower oil, sunflower oil, linseed oil, teaseed oil, chaulmoogra oil, menhaden oil, sardine oil, spermaceti, sperm oil, whale oil, fish liver oils, vitamin concentrates, beeswax, wool fat, castor oil, almond oil, cocoa butter, cashew nutoil, cashew nut shell oil, chicken fat, kapok 011, corn oil, rape oil, oiticia oil, perilla oil, tung oil, the full and partial hydrogenated derivatives of these oils, the individual fatty glyceride acids therein and mixtures thereof. Amongthe suitable modifying agents which may also be employed during the deodorization I are the following: Citric acid, malic acid, malelc acid, fumaric acid, aconitic acid, citramalic acid, itamalic acid, citraconic acid, paraconic acid, itaonic acid, protaconic acid, isaconic acid, mesaconic acid, mucic acid, tartaric acid, tartronic acid, hydroxyglutaric, trihydroxyglutaric, and

\ other hydroxy and/or unsaturated polycarboxylic and a vacuum of about twenty-nine inches of mercury. Some of the samples were deodorized without an antioxidant'and the refined soy bean oil, hydrogenated to a melting point of about 100 F., added subsequent to the deodorization treatment. In others the same antioxidant was added prior to deodorization and was present in all subsequent tests. The following table indicates the results obtained from these tests:

It is apparent from the foregoing resultsthat acids or their esters or anhydrides; resorcinol, pyrogallol, pyrocatechol, hydroqui'none, phloroglucinol, gum guaiac, hexylresorcinol, dihydroxynaphthalene, their low molecular weight fatty acid acyl derivatives or their low molecular weight fatty acid partial ester derivatives; and mixtures of any of the foregoing materials.

Antioxidants, solvents, and other modifying agents may also be incorporated in the fatty acid composition under treatment. Among these materials are glycerol, polyglycerols, ethylene glycol, polyglycols, propylene glycols, tetrahydrofurfuryl alcohol, ethyl alcohol, acetic acid, propionic acid,

' lactic acid, phosphoric acid, salicylic acid, benzoic acid, pyrogallol-acetone condensation product, aminophenols, hydroxynaphthalenes, fatty acid partial glycerides, fatty acid alkylolamides, amino-esters of fatty acids, and the like, The use of the ultimate composition. determines the type of agent which may be so incorporated.

Obviously, many modifications and variations of the invention hereinbefore set forth may be made without distinguishing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. The process which comprises steam dedorizing a, relatively non-volatile fatty material in the presence of an oil of the class consisting of hydrogenated refined soy bean oil and hydrogenated refined sesame oil, said oil having a melting point of at least F.

2. The process which comprises steam deodorizing a fatty acid ester of a polyhydric alcohol under vacuum and in the presence of a small amount of a hydrogenated refined soy bean oil having a melting point of at least 100 F.

3. The process which comprises steam deodorlzing a relatively non-volatile fatty acid ester underi vacuum and in the presence of 0.5 to 5% of a material of the class consisting of hydrogenated refined soy bean oil and hydrogenated refined sesame oil, said material having a meltthe presence of 0.5 to 5% of hydrogenated re-- fined sesame oil having a melting point of at least 100 F.

6. The process which comprises deodorizing a fatty acid ester of low volatility with steam while under a vacuum of at least 2'7 inches of mercury and at a. temperature of at least 200 F., and in the presence of a small amount or material of the class consisting of hydrogenated refined soy bean oil and hydrogenated refined sesame oil, said material having a melting point of at least 100 F.

7. The process which comprises deodorizing a normally reverting fatty acid triglyceride with steam while under a vacuum of at least 27 inches of mercury and at a temperature of at least 200 F., and in the presence of about 0.5 to 5% of a hydrogenated refined soybean oil having a melting point of at least 100 F.

8. The process which comprises deodorizing lard with steam while under a vacuum of at l least 27 inchesof mercury and at a temperature -of about 200 to 300 F., and in the presence of about 0.5 to 5% of hydrogenated-refined soy bean oil of a melting point ofat least 100 F. thereby obtaining a refined non-reverting bland.

lard. I

9. The process of stabilizing fatty materials which comprises adding to the fatty materials a small amount of an oil of the class consisting of hydrogenated refined soy bean oil and hydrogenated refined sesame oil, said oil having a melting point of at least 100 F., and subjecting the mixture to deodorizing conditions by heating the mixture to temperatures of about 200 v F. to 300 F. andpassing steam through the under vacuum.

GUY W. PHELPS. HOWARD C. BLACK.

heated mixture while 

